The rapid growth of the global population and corporate interests has exacerbated issues associated with increasing energy consumption, insufficient waste managementWaste management, and environmental degradationEnvironmental degradation. The 5Rs (Reduce, Reuse, Repair, Recover, and Recycle) form the basis of contemporary methods that address these challenges effectively. There is a practical solution for materials that cannot be recycled: transformation of waste into energy, or WtEWaste-to-Energy (WtE). In WtEWaste-to-Energy (WtE), the system processes include biological conversion (anaerobic digestionAnaerobic digestion, fermentation) and thermal conversionThermal conversion (incinerationIncineration, gasificationGasification, and pyrolysisPyrolysis) and physicochemical conversion (transesterificationTransesterification). While the ecological processes involve in WtEWaste-to-Energy (WtE) includes microbial decomposition (breakdown of organic wasteOrganic waste by microorganisms), thermophilic digestion (high-temperature decomposition of organic wasteOrganic waste) and photodegradation (breakdown of organic wasteOrganic waste by light). Therefore, this chapter systematically evaluates various waste-to-energy processes, emphasizing their capacity to reduce waste. The processes encompass pyrolysisPyrolysis, petrol generation, anaerobic digestionAnaerobic digestion, and combustionCombustion. Sustainable materials management, improved landfill mining, and integrated waste managementWaste management represent effective complementary strategies for environmentally responsible waste disposal. A thorough review of current research and technology developments has highlighted the following environmental impactsEnvironmental impact of waste-to-energy transformations: a shift towards more sustainable energy sources, less waste in landfills, and lower emissions of greenhouse gasesGreenhouse gases. The results show how important it is to generate Waste-to-Energy (WtEWaste-to-Energy (WtE)) to enhance energy efficiencyEnergy efficiency, reduce the environmental impactEnvironmental impact of manufacturing, and advance the circular economyCircular economy. This chapter concludes by proposing directions for additional research and media focus that may enhance the ecological benefits of waste-to-energy (WtEWaste-to-Energy (WtE)) projects.